(a) Field of the Invention
The present invention relates to animated signs and displays and more particularly to those signs and displays in which an animation effect is produced by sequential illumination of the various views of a scene comprising the complete display scene.
(b) Description of The Prior Art
Hilgenberg, in U.S. Pat. No. 1,930,359, Oct. 10, 1933, discloses the use of two transparent sheets with sand-blasted alternate views of a scene. The sheets are alternately edge-illuminated with two tubular gas-discharge lamps to produce the visual sensation of motion of the object depicted from one scene position to the other scene position.
Rupp, in U.S. Pat. No. 2,107,767, February 8, 1938, discloses the use of an electromagnetically operated ratchet to interpose various colored filter glasses between the edge of a glass panel bearing sand-blasted messages and a tubular lamp illuminating the edge of the glass panel.
Ward, in U.S. Pat. No. 2,015,170, Sept. 24, 1935, discloses the use of visible light and short-wave ultraviolet light to alternately illuminate a sign. One scene on the sign is visible in ordinary white light, while a second scene rendered in short-wave ultraviolet responsive phosphors is deposited over the visible image. According to Ward, illuminating the sign with short-wave ultraviolet radiation "will render the secondary (u.v. responsive) design luminous to the extent of almost, if not quite completely, obscuring the colors of the primary (visible) design."
Herberger, in U.S. Pat. No. 2,223,685, Dec. 3, 1940, discloses use of an opaque perforated panel containing one view of a scene, and a solid translucent panel positioned behind the perforated panel and containing a second view. The front panel is illuminated by ambient light or a light source positioned so as to illuminate the front panel at high angles of incidence. Intermittent illumination of the translucent rear panel by a light source behind it makes the scene contained on the rear panel visible, and the scene on the front panel less visible because of the higher surface brightness of the rear scene.
Switzer, in U.S. Pat. No. 2,689,917, Sept. 21, 1954, uses "fluorescigenous" illumination (unfiltered black light, 3500 .ANG.-4500 .ANG.) to edge-illuminate an ultraviolet-transmission panel. The illumination is trapped in the panel by total internal reflection except where the reflection is frustrated by fluorescent paint applied to the surface in the form of "indicia", i.e., figures and advertising messages.
Davis, in U.S. Pat. No. 3,399,476, Sept. 3, 1968, discloses the use of vertical tubular lamps to edge-illuminate a vertical stack of three horizontal rows of transparent slabs bearing messages. Each slab consists of three transparent sheets laminated together and bearing different visible figures. A tubular motor-driven shutter containing vertical apertures is positioned coaxially over the tubular lamp. Rotation of the shutter causes successive illumination of front, middle and rear sheets in the top slab, followed by sequential illumination of the sheets in the middle slab, and finally by the sequential illumination of the sheets in the bottom slab.
Frois, in U.S. Pat. No. 4,244,130, Jan. 13, 1981, discloses the use of a horizontally positioned tubular lamp within an enclosing, motor driven coaxial cylinder. The shield contains an array of identical longitudinal slots positioned around the circumference of the cylinder. Light from the tubular lamp sequentially illuminates a stack of parallel, vertically-positioned acrylic sheets. The sheets have vertically staggered patterns of concave depressions simulating bubbles on successive sheets in the stack. The cross-sectional shape of the sheets is in the form of a bottle, and sequential illumination of the sheets produces the visual impression of bubbles rising in the bottle.